The aim of this study was to evaluate the interspecies variation in oxalic acid (OA) concentrations of leaves between Atriplex canescens, A. halimus, A. nummularia and Cassia sturtii. Significant differences in the oxalic acid concentration were noted between the three Atriplex spp. and C. sturtii at Hatfield. Cassia sturtii at Lovedale also had a significantly lower OA concentration than the Atriplex spp. No significant differences were noted between the Atriplex spp. at Lovedale, although the species at Lovedale contained significantly higher OA concentrations than at Hatfield. The OA concentrations recorded in this study were not considered to be toxic to grazing livestock.